cannot take sizeof a managed array
The sizeof operator gets the value of an object at compile time. The size of a managed array (or managed class) is dynamic and cannot be known at compile time.
For example, the following sample generates C3608:
#using <mscorlib.dll> void main() { int i; __gc int arr[]; arr = new __gc int[6]; i = sizeof(arr); // cannot use sizeof on managed array Console::Out->WriteLine(i); }